Functional safety is a critical requirement in many modern applications. In the automotive industry, functional safety is defined within the ISO 26262 Functional Safety Standard, which is an adaptation of the industrially broader Functional Safety Standard IEC 61508 for Automotive Electric/Electronic Systems.
Power management is a key area of functional safety within the automotive industry, as well as within electrical/electronic industries more generally. Overcurrent, or excess current, is a situation where a larger than intended electric current exists through a conductor, leading to excessive generation of heat, and the risk of fire or damage to equipment. Possible causes for overcurrent include short circuits, excessive load, and incorrect design. Current limiters are commonly used protection mechanisms to control the risks of overcurrent. Conventional current limiters comprise a static/fixed maximum current limit whereby current flow is prevented from exceeding the static/fixed maximum current limit.
However, in many modern applications, and in particular automotive applications, microcontroller units (MCUs) have complex power modes, so an MCU will often be running at a reduced current level well below a maximum required current level. As a result, when the MCU is running at such a reduced current level, faults or other error conditions may be occurring and causing extra current flow, but which would not be detected by a conventional, static overcurrent mechanism because the overall current flow may still be below the static/fixed maximum current limit.